What are the recommended charging habits for the iPhone?

I’ll quote some other guy:

As an electrical engineer, I’ll tell you that Li-ion batteries do have a ‘sweet-spot’ that extends their life. If you discharge the battery to 35–38% charge remaining and then charge it back up to full, the battery will operate more efficiently over time, and last longer.

@squirbel
Many thanks!

Not a prob, I just learned something myself :)

I’ve been fully discharging mine…

The Apple Web site says to fully discharge and charge it once per month to ensure calibration, but I’d also believe the above.

My iPhone’s never reached below 10% battery, I use it during day and put in dock to charge overnight, figured while it’s sitting there I’ll charge it, in case I don’t get time to charge and have to use it for longer next time.
Always done that with all my phones.

How do you tell when its 35–38% on an iPod Touch?

Yes. What you should do is completely use up the battery once a month. This calibrates the battery. Just like how most do on laptops. Completely drain, Fully charge without using and leave it in for a few extra hours.

You should also do this when you first get the iPhone. I can’t explain how happy I am with my battery.